How to do two variables in an if condition? Here I have few else ifs and I want a 100 else ifs! Is there a shorter way?

$(document).on('click', '.btn-next', function () {
                                var z = [];
                                var recipientsArray = z.sort();
                                var zDuplicate = [];
                                $('option:selected.exclude_global').each(function() {
                                z.push($(this).val())});
                                for (var i = 0; i < recipientsArray.length - 1; i++) {
                                if (recipientsArray[i + 1] == recipientsArray[i]) {
                                zDuplicate.push(recipientsArray[i]);
                                }else if(recipientsArray[i + 2] == recipientsArray[i]){
                                zDuplicate.push(recipientsArray[i]);
                                }else if(recipientsArray[i + 3] == recipientsArray[i]){
                                zDuplicate.push(recipientsArray[i]);
                                }else if(recipientsArray[i + 4] == recipientsArray[i]){
                                zDuplicate.push(recipientsArray[i]);
                                }

                                }
                                if(zDuplicate.length>>0){
                                    alert("Global Filter Already Exists");
                                    event.preventDefault();
                                }
                });

Here I have few else ifs and I want a 100 else ifs! Is there a shorter way? I have a dynamic table with dynamic rows. when my table has 5 rows the code is working, but when I have more its not working.